/*
 * Copyright 2016 Open Networking Laboratory
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.onosproject.yangutils.parser.impl.listeners;

import org.onosproject.yangutils.datamodel.YangStatus;
import org.onosproject.yangutils.datamodel.YangStatusType;
import org.onosproject.yangutils.parser.Parsable;
import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
import org.onosproject.yangutils.parser.exceptions.ParserException;
import org.onosproject.yangutils.parser.impl.TreeWalkListener;

import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.removeQuotesAndHandleConcat;
import static org.onosproject.yangutils.utils.YangConstructType.STATUS_DATA;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_CONTENT;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;

/*
 * Reference: RFC6020 and YANG ANTLR Grammar
 *
 * ABNF grammar as per RFC6020
 *  status-stmt         = status-keyword sep status-arg-str stmtend
 *  status-arg-str      = < a string that matches the rule
 *                         status-arg >
 *  status-arg          = current-keyword /
 *                        obsolete-keyword /
 *                        deprecated-keyword
 *
 * ANTLR grammar rule
 * statusStatement : STATUS_KEYWORD (CURRENT_KEYWORD | OBSOLETE_KEYWORD | DEPRECATED_KEYWORD) STMTEND;
 */

/**
 * Implements listener based call back function corresponding to the "status"
 * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
 */
public final class StatusListener {

    private static final String CURRENT_KEYWORD = "current";
    private static final String DEPRECATED_KEYWORD = "deprecated";
    private static final String OBSOLETE_KEYWORD = "obsolete";

    /**
     * Creates a new status listener.
     */
    private StatusListener() {
    }

    /**
     * It is called when parser receives an input matching the grammar
     * rule (status), performs validation and updates the data model
     * tree.
     *
     * @param listener listener's object
     * @param ctx context object of the grammar rule
     */
    public static void processStatusEntry(TreeWalkListener listener,
                                          GeneratedYangParser.StatusStatementContext ctx) {

        // Check for stack to be non empty.
        checkStackIsNotEmpty(listener, MISSING_HOLDER, STATUS_DATA, "", ENTRY);

        YangStatusType status = getValidStatus(ctx);

        Parsable tmpData = listener.getParsedDataStack().peek();
        if (tmpData instanceof YangStatus) {
            YangStatus yangStatus = (YangStatus) tmpData;
            yangStatus.setStatus(status);
        } else {
            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, STATUS_DATA, "", ENTRY));
        }
    }

    /**
     * Validates status value and returns the value from context.
     *
     * @param ctx context object of the grammar rule
     * @return status current/deprecated/obsolete
     */
    private static YangStatusType getValidStatus(GeneratedYangParser.StatusStatementContext ctx) {

        YangStatusType status;

        String value = removeQuotesAndHandleConcat(ctx.status().getText());
        if (value.equals(CURRENT_KEYWORD)) {
            status = YangStatusType.CURRENT;
        } else if (value.equals(DEPRECATED_KEYWORD)) {
            status = YangStatusType.DEPRECATED;
        } else if (value.equals(OBSOLETE_KEYWORD)) {
            status = YangStatusType.OBSOLETE;
        } else {
            throw new ParserException(constructListenerErrorMessage(INVALID_CONTENT, STATUS_DATA, value, ENTRY));
        }

        return status;
    }
}